Santa Clara electricity customers would see their rates jump between 4 percent and 13 percent if the city invested from $50 million to $200 million in utility funds for a new 49ers stadium, according to a mountain of utility data released Monday.

The assessment – which drew concern from the 49ers – comes as the team and some community leaders are eyeing the city-owned utility’s flush cash reserves as a potential funding source for a new $800 million stadium near Great America. It also offers the first estimate of how Santa Clara residents may be asked to help pay to bring pro football to town.

A residential customer with a typical power bill of $45 a month would see an increase of roughly $1.80 to $5.85 a month, said John Roukema, assistant director of Silicon Valley Power, Santa Clara’s municipal electric utility.

The utility already operates at a deficit – with a projected shortfall of about $26 million this year – but uses its unusually large reserve of cash to keep the city’s electricity prices significantly lower than utilities such as Pacific Gas & Electric.

“We need a rate increase even now” to maintain the proper cash reserves rating agencies require public utilities to carry, Roukema said. Even if nothing were spent on the stadium, Santa Clara utility officials say they would need a 3 percent rate increase in 2008 because the utility’s cash reserve is earmarked to rebuild substations, improve transmission lines and make other improvements.

A 49ers spokesman Monday said the team needs more time to review the city report, which was released late in the afternoon. But with San Francisco making a renewed push to keep the 49ers – city officials unveiled updated plans at a neighborhood meeting Monday for a stadium at the former Hunters Point Naval Shipyard – the electric rates warning could represent a turning point in Santa Clara’s previously untroubled relationship with the team. Pete Hillan, a 49ers consultant, said City Manager Jennifer Sparacino’s report to the mayor and city council could “prematurely eliminate” debate on the utility fund idea first proposed by former City Manager Donald Von Raesfeld.

`Creative’ solution

The stadium “will create thousands of jobs and create millions of dollars in tax revenue for the city,” said Hillan, who said the team liked Von Raesfeld’s idea. “We’re concerned about any attempt to prematurely eliminate his idea. If we are able to build a stadium that would create jobs and have economic benefits, without raising new taxes or impacting the general fund or jeopardizing ratepayers, we will need bold and creative solutions.”

Using utility reserves is just one of the options, such as development of city-owned land, for what could be up to a $200 million public investment the 49ers say they need from Santa Clara to help finance a stadium. The 49ers have been adamant about not seeking a tax increase or tapping the city’s general fund for the stadium. Team owner John York wrote in a letter Monday to the editor of the Mercury News that tapping the utility reserves to help finance the stadium “could be an option as long it does not impact ratepayers.”

The report issued by Sparacino suggests that rate increases could happen as soon as January 2008:

If the utility spent nothing for the stadium, it forecasts a $31 million deficit in the 2007-08 fiscal year, even with a 3 percent rate increase in January 2008.

If it set aside $50 million for the stadium project, the utility would be facing a $76.3 million operating deficit, even with a 7 percent rate increase that includes 4 percent for stadium spending.

If it spent $200 million for the stadium in the coming fiscal year, the projected deficit would be $216 million, even with a 16 percent rate increase that includes 13 percent for the stadium.

Tapping into savings

Although stadium construction isn’t scheduled to start until 2010, the utility would be forced to segregate the stadium money immediately, Roukema said. Tapping the utility reserves for the stadium would also require a vote by residents to change the city charter.

As of Jan. 31 Silicon Valley Power had about $387 million in cash reserves, including a $241 million “cost reduction fund” to cushion ratepayers from jumps in electric rates and to pay for capital improvements, according to the data released Monday.

The utility acquired much of the nest egg during the energy crisis that gripped California in 2001, when the utility had excess energy and was able to sell it to the power grid at then-inflated prices. By selling that power, the utility saw its cash swell from $187 million in 2000 to $371 million a year later.

The utility’s reserves are now the crux of the debate about whether, or how, Santa Clara helps the 49ers pay for a 68,000-seat stadium the city would own.

Von Raesfeld has described the utility cash as a “fantastic opportunity” and an under-performing asset that could be harvested for the 49ers’ stadium. But city officials maintain the financial reserve is a crucial part of prudent management and a tool to keep electricity bills low.

The city-run utility’s 43,000 residential customers currently enjoy a bargain: Their electric bills are 48 percent lower than those of PG&E. Commercial customers pay 27 to 37 percent less than PG&E, while industrial customers pay between 23 and 29 percent less than PG&E, according to city data. Two 5 percent rate increases in 2006 were the first raises in 13 years.

If the utility were to forgo or reduce needed capital improvements, and instead use its reserves to finance a stadium, the rating agencies would probably take a negative view of that decision, said Chloe Weil, an analyst with Fitch Ratings in New York City who follows Silicon Valley Power.

“They would have to make up those funds from somewhere,” she said, “and it’s ultimately going to fall on their end users at some point.”